class Animal:
    def __init__(self, name):
        self.name = name

    def make_sound(self):
        pass


class Dog(Animal):
    def make_sound(self):
        print(f'{self.name}说汪汪')


class Cat(Animal):
    def make_sound(self):
        print(f'{self.name}说喵')


dog = Dog('小白')
dog.make_sound()
cat = Cat('小花')
cat.make_sound()

print('')
